Concentrating and dehydrating apparatus and method



J. M. HALL CONCENTRATING AND DEHYDBATING APPARATUS AND METHOD Filed Nov.A14, 1938 3. Shevets--Sheet` 1 /mw AMA .1.1. HHH` y wy., ./w. QM mmm wwwmw NN l J. M. HALL 2,217,547

CONCENTRATING AND DEHYDRATING APPARATUS AND METHOD oct. s, 1940.

s sheets-sheet 2 Filed Nov. 14, 179158 Oct. 8.x' 1940. 2,217,547

I CONCENTRATINGAND DEHYDRATING APPARATUS AND METHOD J. M. HALIL FiledNov, v14, 193e sheetsfsAg-'em 2. O j ,w a D@ n, o w n \V 6 9 9 @ww 9% A7 6 D@ 3 J 0 M 7 J 5 J 9 /l d N. m m. f ,6 0 w f,

. @jy/2 M Ha www? @LT1/aw Patented oct. 8,1940

, "This invention relates to systems for dehydrating 'liquid productsand the like.

1 One of the objects of the invention is' tln proi vision of a new andimprovedapparatus and Y method for dehydrating liquid products byutilizing a'drying gaseous mediumtogether withnovel means for assistingin separating thedrying medium from thedehydrated particles of theproduct.,;

Another object of the invention is the provision of a dehydratorchamber,Y having new and improved means for dehydrating aliquid productand rfor efficiently vseparating the dehydrated particles. from thedrying medium in a single chamber ina continuous operation.A f y f Otherand further objects of therinvention are the provisioncf a new andimproved. apparatus for. concentratinganddehydrating liquid productsthat is comparativelysimple in conv struction, .effective inoperation,andlthat is adapted to dehydrate liquid products without affecting thechemical composition of the prod'juct or changing-its physicalcharacteristicsexcept-to remove the moisture.

vOther and Vfurther. objects and advantages' of the invention willappear from the following descript-ion taken, in connection with the,accom#- panying drawings, in -which- Fig. 1 is a side elevation of aliquid product concentrating, dehydrating and collecting apparatus,shown more or less diagrammatically, with parts -broken away and partsin section;

Fig. 2 isa side elevation of a liquid product dehydrating and collectingapparatus, shown more or less diagrammatically, with parts in sectionand'parts broken away;. l.

Fig. 3 is a top plan View of the; mechanism at the upper end of thedehydratorwth the.

dehydrator casing removed for the sake ofclear- 4o ness; v

Fig. 4 is aside elevation of a portion cf the collector mechanism, withparts broken away;- Fig. 5 is a top plan view thereof Fig. 6 vis avertical section through; an upper 45 portion of the'dehydrator shown onan enlarged scale from that shown in Fig. 1and with'fparts broken away;

Fig. '7 is a section on the line 1--1.of Fg. 6;

Fig, 8 is a'section on the line 8- 8 of Fig. 7; and. 50 Fig. 9 is asection on the line 9'-'-9 of Fig. 7, on`

an enlarged scale'.

It' is common practice, in dehydrating `liquid products, to spray theproduct in lnelydivided particles in toia currentof heatedgaseous vInedi- 55 um and then to separate the dehydrated par ticl'esi'rfr'om the'`gas'eous medium centrifugal n iechanism.y y Great diiii'culties. havebeenf jencountered in thedifferenttypes of equipment employed..Insome'typespf apparatus the rna- 1 v,terial is,not'msuiiici'ently.dried vbefore itf c om`es .in to contactjwitli" the' wallsV of thedehydrator chamber. to` prevent its adherence to the'walls contains.sugar such I'as milk 'and thelile, is carvamelizd," whileinothers, sucha large"propor-v tion. of theiines escape from theidehydrator as tonecessitate the use of additional 'equipmenty such as screens, -cr Ythelike. to render the use offsuch equipment economical. L The present in-Y vention avoids these object iorisby .th'euse of a system in whichthematerial is' s otreated that it is sufficiently *dehydratedias toavoidadherence' and isl `suflicient to meetthe requirements of the tradeVand yet visfnot heated toV such an'extent as to aiect the chemicalvcomposition Aof the' dehydrated productf" The critical stag of lthistreatment VAis thatreceived in thegdehydrator chamber but for aifullunderstandingof the operation ofthe 'dehydratoi chamber, the apparatusforconcntrating'- and dehydrating'the liquid.-

product Will befde'scribedf* While any suitable gaseous drying mediummay'beernployed, the apparatuswill be described as vusingsuperheatedsteam atlowpres'sure. i

Infthe present invention, steam is used inwhat may be termed a closedcircuit aszthe dehy drating uid so that `the moisture removedzirom the.liquid particles may also be utilizedasfalpart ofV the cooling medium.But since :the dehydrating fluid is being'added to continuously YfloymoistureI in the Aform of steam from the liquid product during itsdehydration, it is .necessary to continuouslyv remove this extra amountof. moisture, or steam' fromI the `system. .Th is is. accomplished in aneconomical manner by utilizing steam fromthis circuit mixed lwitl 1steam1r from the steam generating mechanismj'iri'what 'may be termedasecondary closed circuit' through an evaporatorand'a' steam 'generatorand utilizing steam from this circuit for .operating the various pumpsand otherl mechanism employed inthe' plant. In 'theevaporaton theYliquid prodi ucty is concentrated preparatory to' being supplied t0thdellydmtorv. y l

In dehydratingmilk and other liquidproducts containing sugar, it isnecessarythat `thevtemperature of the particles shall not-rise to suchanextent as to cramelizethe Asugarv content of the Vmilk/ orother'productv or'ot'herwise injure the solid parti'cles'after' theyhave beendehydrated.

It is obviously necessary that the dehydrating perature of theseparticles to an objectionable extent during the process of evaporationand since the steam or vapor from the moisture vevaporated from Eheliquid particles absorbs a considerable amount of heat from the steam,rendering it latent, the temperature of this superheated steam will bereduced by the time the moisture is evaporated to such' an extent thatthe dried particles are not injured for the exceedingly brief time theyare exposed after being dehydrated. In the use of superheated steam fordehydrating milk, for instance, it has been found that satisfactoryresults may be obtained by introducing the steam into the dehydratingchamber at around 400 l1i'. at substantially"atmospheric pressure andconducting the steam through the chamber at such a .velocity that therewill be a complete change of steam withinthe cham-' ber around threetimes per minute, the product being promptly cooledto around 100 F.after being dehydrated. By employing the principle of the cyclonecollector in removing the solid particles from thesteam and the steamaxially from the dehydrator, long exposure and consequent injury to theparticles by the heat is avoided.

Referring now tothe drawings, the reference character IU designatesgenerally the concentrating and dehydrating apparatus which comprises aboiler` I I, a superheater I2, concentrating or evaporating apparatusI3, a liquid product supply reservoir I4, a. dehydratoror dehydratingchamber or cabinet I5 and a primary collector or separator I6.

The boiler I I may be of any suitable or conventional type and isprovided with a Yliquid container portion I1 'for containing the heatingfluid, as water, Ythat is fed to the boiler by the feedV water heater I8by means of the pump or the like I9 and by Water conducted through thepipe 20 from a suitable source of supply, not shown. The boiler isadapted to be heated by a furnace 2| 4having an oil or other burner 22of anysuitable construction. vThe steam is conducted through thepreheater by a pipe 30 entering the lower portion of the preheater andleaving through the upper end thereof, as shown in Fig. 1.

The flreboxof the furnace is provided with a back wall or baille 23 fordirecting heated gases up into the boiler II for heating the same. Theboiler isv provided with ilues or passages 24 through which the heatedgases are conducted to the stack 25. The water is converted into steamunder pressure in the boiler II and from thence is conducted through thepipe 26 to the superheater, a branch pipe 21 being provided forconducting steam to the motors or engines for operating the variousparts of the apparatus used in the plant. 'Ihe pipe 26 is provided witha pressure `*reducing valve 28 for controlling the amount of steamdelivered to the superheater. The steam in the superheater is maintainedat the desired low pressureby meansjof this valve. y

l The superheater I2 comprisesl a heat exchange member 29 having tubesvor flues'l 29a through which the steam passes and also having a heatingfurnace 3| provided with an oil or gas burner 32 in one wall thereof.'Ihe combustion chamber 33 of the furnace is provided with bales 34 and35 rising from the bottom wall of the combustion chamber and with abaille 36 extending downwardly from the upper wall of the superheaterbetween the walls 34 and 35 so that the heated gases will be caused totravel in a'serpentine path for heating the tubes and superheating thesteam flowing therethrough. The products of combustion, that is, theheated gases are dischargedfinto the atmosphere or escape into the stackthrough a passage 31. The superheater I2 is provided with an antechamberor header 38 within which is mounted a blower or fan 39 which is adaptedto be operated by a motor 50.

This fan is of suilicient capacity to deliver the steam, which is at lowpressure, into the dehydrator at high velocity. The steam from theboiler Il passes through the pipe 26 into the antechamber 38 and aportion of it is.forcedv through the superheater into a passage 4I`leading to the dehydrator I5, sce Flg.2, and another portion of thesteam is forced through a passage to the primary evaporator, as willpresently appear. f

The liquid product, before it is treated, is contained in the reservoir-I4 and is conducted' to the concentrating or evaporating apparatus I3through a pipe 42 having a valve 43 therein for controlling the amountof liquid supplied to the concentrating apparatus. The concentratingapparatus I3 may be of any suitableform and of any desired number ofunits. In the form of the construction shown, which is by Way of exampleonly, twov concentrator or evaporator units 44 and 45 are employed, anysuitable number may be used.

The unit 44 is providedwith a heating portlo or heating chamber 46 whichmay be regarded as a heating jacket and a liquid containing portion 41.In the form of the construction shown, the unit comprises an elongatedcasing 48 having tube sheets 49 and 5I spaced from the ends thereof inwhich the ends of the vertical tubes 52 are secured. Thesesheets andtubes divide the unit into an upper header 53 and a lower header 54which are: connected together through the tubes 52. The space around thetubes between the sheets constitutes the heating chamber or heatingjacket 46 rfor heating the tubes containing the liquid product forevaporating a portion of the moisture therefrom. The pipe 42 conductsthe liquid product from the reservoir I4`to the lower header 54. Aconduit 55 is adapted to conduct a portion of the heating fluid flowingthrough the antechamber 38 of the superheater tothe steam chamber orjacketv 48 of the heatingunit 44 for heating the liquid product therein.This conduit 55 also constitutes a vent for removing excess steam formedin the dehydrating circuit from the moisture evaporated from theparticlesof the liquid product during its dehydration.

It is desirable that the heatingfluld used in concentrating the liquidproduct which, in the present instance, is steam, be confined to aclosed circuit so that it may be used over and over again therebyconserving the heat contained in the water of condensation.

In the form of the device shown, the jacket 46 is connected as bymeansgof a passage or pipe 56 to the feed water heater I8 and fromthence the fluid is pumped by the pump I9 through pipe 51 into theboiler II. Fresh Water is introtheunit. 45 belower than that Yin -theunit 44 so that the steam will i'low .in that direction. As shown, theheader 44 is provided with apassage 59 which is in communication with a.liquid collector SI-having a baffle 62 whereby particles of the liquid'product passing over with the `steam through the passage 59, due tothe'violent ebullition in the unit 44,` will be directed downwardly and'be .collectedin .the bottom of the chamber'` and the steam separatedfrom these particles will pass over by a passage |`3 into the steamcham- Since the unit 45 is of substantially the same construction 'asthe unit 44, it .is not thought necessary to repeat the descriptionofthe same atthis point any further than to state that it is vprovidedwith an upper .header 53a, a lower header 54a and a steam jacket 48a,the same as the evaporator or concentrating unit 44. y The upper header53a is4 in communication witha liquid collector 65 which is ofsubstantially the same construction as the collector 6|. The co1.-lector 65 is in communication with a condenser 66 through a pipe 61connected to their upper The lower -headers 54 and portions and thecondenser is in turn in communication wtih a vacuum pumpV 68 through aconduit or pipe 19. The condenser 66 is adapted to be supplied with coolwater through pipe 69 by-a pump 1|a`which forces the same through thecondenser and out throughthe pipe 1| in amanner well known in the art.`Steam is supplied to the pump 68 from the pipe 21 through the pipe fmunication through a piper12-which is also in communication withthecollector 6| through a pipe 13. A pipe 16 having a pump 15 associatedVtherewithis inY communication with the lower end of the collector 65. Abranch pipe 11 places the pipe *16. and the'header 54a in communication.In order to reduce the pressure within the steam jacket 64, a pipeu18 isinl communication with the lowerpart ofthe jacket 64 and with a pipe 19leading from the condenser 66 to the vacuum pump- |58. Avalve 8| isinterposed in the pipe 18 for controlling the amount of pressure in thesteam jacket 64. Since vthe steam jacket 64 is in communication with thevacuum pump68 through Ithe pipes18` and V19and the steam jacket 64 isalso. in communication with;

the collector 6| and with the headerj 53, it ls evident that the headers53 and 53amay be maine tained at subatmosphericpressure, the header 53dbeing'maintained at lower pressure'than the header 53. By means ofthis-arrangement,the` liquid passes from the evaporator 44 to the`evaporator 45 by the Ydiiierence in pressure therein and due to thisdifference in pressuref-thev' liquid in thefevaporator 45 is boiled atalower .temperature so that the steam passing Aover through the pipe 63willtfurther concentrate the liquid in the evaporator 45. Theconcentrated liquid is ksupplied through the pipe 14-.by the ber orjacket 64 of the second concentrating unit 54a are in come pump 15 tothedehydrator |5thefamount being controlled by a valve 82 inthe pipe 14.,4

The -.dehydrator I5 isof thecyclone collector typeand comprises a casinghaving an upper cylindrical portion 83.and `a lower tapered por--v tion84.` The taperedportion 84, von ythewalls of which thev dehydratedmaterialis thrown by centrifugal action, isprovided at its lowerend"with a rotaryl valve 85.1501' the discharge ofthe dehydratedjmaterial.This valve isvoperatedby a motor 86 in 4a. manner well known in the art.

Suitable means are provided for atomizing'the concentrated liquidproduct deliveredlto theridehydrator I5V through the pipes 14 from Qtheevaporators. In` the form of the construction shown, Va rotating head81y is employed for atomizing -theconcentrate. This head isfvate tachedto a rotating spindle 88, Fig.' 9, which-vextends upwardly. throughfatapered casing 89 ar ranged axially of the dehydrating chamberV I5 andsecured vat its upper end to a` plate 9|` which in turn-.is secured tothe casing92 whichy .constitutes the return conduit for the superheatedsteam, as will presently appear. f I

Mounted on the plate 9|v is'a motor 93, the armature of whichistintegral with, or rigidly connectedfto the spindle 88. Thespindle88x'is munication with' the outer end of the' pipe '1.4. Thehead? 81 is' provided with' an upwardlyfex tendingv hub95 which is keyedto the lower end of 'the spindle 8.8,'see Fig. 9, and rotatestherewith.v VThis' hub'is rotatably mounted' in v'a cap 96detachablyconnectedto the lower endof vthe housing 89 as shown moreclearly in Fig. 901! the drawings. f l l j Suitable anti-*frictionbearings 91 are' employed` betweenV the'hub 95and cap 96. v'The cap 96is providedon its lower end'e-with'a recessy 98 fo'i' receiving excessvlubricant ydirected therenfby the deector 99. Oil is adaptedltobef'supplied tothe bearings through apipe |0| extending vupwardlythrough the casing89.-" Y' The hub 95 is providedwith a recessorreceptacle |02 in its lower portionfor providing a reservoir .forconcentrate deliveredv through ythe provided', with an'axial bore 94lwhich is in comf avc pipe 14 andv the bore 94-in the spindle 881' Castintegral: with thehub orrigidly securedthereto are ajpluralityjoi arms|03, fourv being shown, each oflwhich is provided with abore or passageradially from the reservoir |01.V foridlscharging theconcentrate whichis maintained under lpres;l sure inthe-reservoir |02 by thepump'15. ATheouter endfportions of the arms =|03 areconnected together by arcuatemembers forminga circle |05. iThis. circle vis concentric withtli'ef-axls" o f the spindle88 and reservoir |02 whereby the airresistancey tothe turning of the arms will be reduced toaminimum.' Thearms |03 extend outwardly beyond the circle l05fand=form discharge*nozzlesl |06 which are in alinement'wlth the passages |04 in the' arms|03.y The arms |03`are so lfashioned that they will constitute theyanes.of an exhaust :fan for exhausting steam: from n the' dehydrator, aswill presently appear.

' In cross-section,y the arms will ybe more or'less vflat on theiradvancing side ina plane at anl angle Vto v,the 1horizontal as shown atVl |,0in Fig. `8. These 'blades exhaustthe steam or vapor from thedehydrator and' dischargev theisame' into the return conduit AH4 on`the.intake sideofQthe fan or blower 39.. Thearcuatehmembers orv bracesv |05are located beneath the lower end of the-:cas-

5c m4" extending lengthwise jthereef, v that;y is;k

ing |08 and assist in closing the space between said casing and arms.

Suitable means are provided for dehydrating the concentrate delivered tothe dehydrator by the atomizing head 81. In the Vpresent invention,superheated steam is employed for this purpose. The steam from thesuperheater 29 is forced through the conduit 4| into the upper end ofthe dehydrator. In the form of the construction shown, the conduit 4| isin communication with a snail passage |01 extending about the housingl89, Fig'. 3. The .iail will cause the steam to rotate aboutaverticalaxis as it is being delivered to the dehydrator. Thissteam is directedacross the periphery of the rotating spray head that is, across thenozzles |06, by means of a casing |08 which is attached to the returnconduit ||4 of the fan. The steam or drying medium is caused, by thesnail |01, to rotate in the same direction-as the'head 81, as shown bythe Varrows in Fig. 3, and the rotation of the nozzles assists Vinincreasing the rotation of the incoming drying medium. The casing |08 isin communication with the return conduit ||||y of the fan 39, as willpresently appear. It surrounds the housing 89 and is spaced therefrom.The lower end of the casing |08 is ared outwardly as at |09 'fordirecting the rotating stream of steam outwardly and downwardly. Aconverging conical casing attached to the snail and to the upper wall 2of the dehydrator is employed for directing thelstream downwardly andinwardly.. This casing has its lower end curved'outwardly as at |3 so asto cooperate with the curvature |09 to direct the steam outwardly anddownwardly across the discharge nozzlesas they are rotating therebyassisting in atomizlng the concentrate and removing the moisture`contained in the particles.` This steam or drying medium and theparticleswill be caused to move outwardly and then downwardly in anouter spiral in the dehydrator and the dry particles will be thrownoutwardly by centrifugal force and collected in the bottom yof thedehydrator and the steam or drying medium will thereafter move upwardlytoward theldistributorhead in an upwardly moving inner spiral in contactwith the outward spiral and rotating in thel same direction, asindicated in Fig. 3, whereby the fine material carried over into theinner spiral will be thrown by centrifugal action into the outer spiraland the steam or drying medium vwill be withdrawn by the suction of thefan 39 and head 81 axially through the casing |08 into a return conduit||4 which is connected with the intake of the fan 39. It will thus beseen that the drying medium, on entering the dehydrating charnber, owsoutwardlyV toward the side walls of the chamber` and then downwardly inan outer spiral pathand that the liquid product is sprayed into themedium as it enters the chamber so that an appreciable length of timetranspires between the time the sprayed material is introduced into theentering mediuml and the contact of they mixture with the peripheralwall of the chamber.k During this time and while thek mixture is movingalong this gradually Widening spiral path, the `particles are dehydratedand consequently will not adhere to the sides of the dehydrator whenthey come into Contact therewith. Some of the finer dehydrated particlesof the product will be carried over into the ascending inner spiral andthe rotation of lthis spiral, which is augmented bythe'rotation of thefan blades ofv the` distributor head 81, will throw these particles, bya centrifugal force, into the outer spiral whereby substantially all ofthe dehydrated particles wlll be collected by gravity within the lowerportion of thev chamber. It will alsobe seen that the superheated steamwill beused for dehydrating the concentrated liquid product in a closedcircuit without being condensed and being promptly removed axially ofthe dehydrator will not injure the dry particles that are movingcircumferentially of. the dehydrator cone.

By means of the valve 28,'the steam generated in the primary boiler vorheater may be maintained at any desired pressure for operating the primemovers of the entire system, such as the pump 68 and the like, while`the steam within the superheatingI circuit is being maintained at lowerpressure.v By means of kthe valve 28, the steam generated in the boiler24, or at least a lpart of it, is permitted to expand into thesuperheater 29 where its temperature is greatly increased and itspressure maintained substantially constant at a little, if any, aboveatmospheric. It has been found that steam at about atmospheric pressurewith a temperature of around 400 or I450' F. gives satisfactory resultsfor dehydrating atomized liquid particles in the dehydrator. The pipe 55may bek regarded as a vent for the steam in the dehydratng circuit andwith the aid of the valve 58,-the pressure within this circuit may bemaintained substantially constant. The excess moisture introduced intothis circulating system from the moisture evaporated from the liquidparticles in the dehydrator is conducted to the primary boiler throughthe evaporating circuit and is taken from the system through pipe 21 assteam under pressure and utilized for operating motors or engines usedin the plant. The exhaust from these engines is used in the preheaterasa heating medium. This added moisture, if not sufficient, maybeaugmented bythe feed pipe 20 from a source of water supply.

The dehydrated product escapes from the dehydrator at elevatedtemperature, too hot to be placed in containers, and in order to lowerthe temperature, the product is discharged by the valve 85 into aconduit i|5 having a valve ||6 which will admit fresh cool air drawninto the conduit ||5 by the fan in the secondary collector |I8 forcooling the product. The conduit ||5 leads to the cyclone separator |6into which it discharges the air and desiccated product tangentially inthe usual manner.

The air is withdrawn from the collector axially thereof by the fan inthe secondary collector ||8. It passes through a snail ||1 into thesecondary collector ||8 which will collect any residue productescaping-with the air from the primary collector I6. This collectorwilldischarge the separated material through a` conduit ||9 back intothe primary collector I6 and the separated air will be dischargedthrough a suitable passage |2| in the uual manner. Since the cycloneseparator I6 and the secondaryseparator are of the usual or any wellknown construction, it is not thought necessary to describe thesame indetail. The cooled dehydrated material is removed from the separator |6`through a rotary valve operated by a motor 90.

In thefoperation of the system, steam from the boiler is conductedthrough the pipe 26 to the header 3B andV forced through the conduit 4|through the snail |01 and introduced into the dehydrator in a spiralmovement across the spray of liquidA productthrown outward by the sprayhead 81, asA described above. The steam, being superheated, willdehydrate the p'rductand the centrifugal force willthrow the soliddehydrated particles outward against the walls of thedehydrator andgravity will cause the particles 'to collect in the lower part' ofthedehydrator in the form of dry powder. 'I'his powd'erwis discharged intoa cooling passage` I ,l 5 and airjdrawn through this passage cools the'powder and ydelivers'the same into the air separators where it` andaportion circulated through the jacket 46 of the evaporator 44 andreturned' tothe boiler through the preheater I8. Steam is withdrawn.from the system through the pipe 21which may be so regulated as tovcompensatejfor'the'amount of moisture added tothe system by the`e'va'piiratedrmoisture from the liquid product'.` Preferably, thoughnot necessarilyymeans` s uch as the pipe |22 having a valve |23 areprovided for shunting steamunder pressure directly J from the boilerIl'to the steam jacket 46 of the'evap'- oratori for augmenting theconcentration of the liquid contained therein. This shunt may bev causedto operate inconjunction with the steam from the dehydrator circuit orindependently' thereof. Whenfused,` it establishes what may be termed ashunt 'circuit through the-boiler Il and evaporator 44.

If it is desired that the concentrated product be, not dehydrated, itmay be removed through a suitable conduit |20 controlled by the valve I2l.

In the operation of the systemdescribed above, for dehydrating milk, thefollowingk was found to give satisfactory results. The pressure of thesteam in the boiler Il was whatever was necessary to operate the variouspumps and other apparatus in the plant and was around 50 to 70 pounds.The steam or vapor introduced into the dehydrator was around 400 to 450F. and at very low pressure, about that of the atmosphere or slightlyabove. The cubical capacityjof the dehydrator was about 5000 cubic feetandthe velocity of the steam was suchthatabout 15,000 cubic f eet wasintroduced intothe dehydrator per minute. The powder'was discharged ataround 225i F. and was cooledto 100 F. 'The above is given byway ofexamplefonly and it is not here intended that the wordsused shall belconstrued as Words of limitationbutmerely as words of description ofoneform of the devicethat has proven practical.

Itv will thus be seen that by the use of adehydrator that functions as acyclone collector; steam at very `high temperatures may be used withoutinjuring the product. The' lhottest steam contacts the wettest particlesand the moisture evaporated from them prevents their becoming overheatedBy the' time themoisture has been evaporated from the particles, they'will have moved downwardly and have been thrown outwardly bycentrifugal force againstthe inner periphery of the dehydrator and inthe meantime, the steam is drawn toward the axis ofthe dehydrator andexhausted through the top thereof whereby the dry particles aresubjected to the steam just a sufficient interval of time to dehydratebut not injure the same.

rI 'his is considered an important feature of the invention because itpermits the use ofsuper- Y 4:It isV thought same aftery passing throughthe dehydrator is sufficiently hot' to be used' in the primaryevaporator.. v Y c While in the present system superheated steam at lowpressure is employed as the drying gaseous medium, it is understood thatso far as the function of the dehydrator chamber and associatedmechanism is concerned, it is immaterial'what t'ypeof drying'gaseousmedium be employed since the principle of operation would remainunchanged. f j l 1v from the foregoing -taken in' conn'ectiony with rthe'accompanying drawings vthat the ccnstruction and operation of my devicewill `be Aapparent to those skilled in the art, and that changes insize, shape, proportion and details of vconstruction may be made withoutdeparting from the spirit and `scope ofthe appended claims. Iclairn asmy invention: f

1. Ak 'method' of dehydrating a liquidl product which comprisesintroducing a gaseous vdrying medium :into: one end" of a substantiallycircular walled'finternally,unobstructed chamber, causing s aidmedium toilow'outw'ardlyfrom 'the axial zone 'of said chamber and to rotate in' aspiral opposite' end of the chamberand'within the same, causingvsaidmedium to return throughsaid axial zone in'an'inner spiral, currentrotating in the same direction as the outeri current andin contacttherewith toan outlet inthe'rst named end ofthechamber and withinvsaidaxialjzone, and spraying a liquid product substantially uniformly aboutthe axis of said chamber intlth'e outer spiral current only, adjacent tosaid outlet, whereby dried particles will be thrown to the-wall ofthechamber by centrifugal action 'from both currents for collection at thesecond` named end of the chamber. `v

2 .A method of dehydrating a liquid product whichcomprises introducing acurrent .of gaseous drying mediumV into a chamber, causing'said'mediumto flow outwardly and to 'descend' in =an outer spiral within saidchamber to the lower portion thereof4 and in contact'with the side wallof y'said;chamber,`causing said medium to flow upwardlyfrom the lower.portion of saidfchamber to the exterior 'thereof in an inner spiralwithin tinuously introducing a current ofgaseous drying medium into achamber to flow outwardly yin said chamber and. to descend spirally inan outer spiral therein to the lowerportion thereof, causing said mediumtoowupw'ardly from the lower portion of .said chamber to` the exterior'thereof in an inner spiral Within the rstrnentioned spiral' and incontact with the first mentioned vspiral' throughout substantially thewhole axial extent thereofgcentjmifilgally discharging 'a liquid productin finely divided particles continuously outwardly into the vincomingdrying medium only from the inner vzonethereof wherebyfinely dicurrent`outwardly of said axial `zone toward the vided particles will be thrownoutwardly by centrifugal action across the outer spiral for collectionby gravity in the lower portion of said chamber and dried particlesescaping into said inner spiral will be thrown by centrifugal actioninto said outer spiral. v c

4. In a system for dehydrating liquid products, a dehydrating chamber ofsubstantially circular cross-sectionhaving the upper portion of its in'-terior unobstructed, an outer intake conduit extending axiallydownwardly into said. upper portion, a discharge conduit within andsubstantially concentric with said outer conduit whereby a substantiallyannular intake orice is provided between saidl conduits, a distributorhead supported adjacent to, but beneath, said conduits, said head havingmeans for discharging an atomized liquid product outwardly beyond saiddischarge conduit and across said orifice, and mean-s for directing agaseous drying medium through said orifice outwardly across the atomizedproduct against the inner periphery -of the chamber in an outer vspiraldown along said periphery to the lower portion of the chamber, saidmedium thereafter fiowing to said discharge conduit spirally upwardlywithin said outer spiral and in contact therewith, whereby solids may becentrifugally thrown from the outer spiral to the wall of the chamberand from the inner to the outer spiral and thence to the wall of thechamber and gravitate to the bottom thereof. y

5. In a system for dehydrating liquid products, a dehydrating chamber ofsubstantially circular cross-section having the upper portion of itsinterior unobstructed and having a tapered lower portion, an outerintake conduit for conducting a drying medium to said chamber, adischarge conduit Within and substantia-lly concentric with said `outerconduit, both conduits being connected to said chamber axially thereof,whereby 'aesubstanf tially annular intake orice for the chamber isprovided between said conduits, a distributor head supported adjacentto, but beneath, said conduits, said head having means for dischargingan atomized liquid product outwardly across said orifice, means fordirecting a gaseous' drying medium through said orifice outwardly acrossthe atomized product against the inner periphery of the chamber in anouter spiral down along said periphery to the lower portion of thechamber, said medium thereafter flowing to said discharge conduitspirally upwardly within said outer spiral and in contact therewith, andmeans for assisting in moving said medium in said spirally upward path,said head means discharging into the incoming drying medium only,whereby solids may be centrifugally thrown from the inner to the outerspiral and' particles within the outer spiral may be thrown to the wallofthe chamber and gravitate to the bottom thereof` 6. In a system fordehydrating liquid products, a dehydrating chamber of substantiallycircular cross-section having the upper portion of its interiorunobstructed, an outer-intake conduit and an inner substantiallyconcentric discharge con'- duit both extending axially downwardly intosaid upper portion and having their inner ends outwardly flared wherebya Asubstantially annular intake orifice is provided between said ends, adistributor head supported adjacent to, but beneath, said conduits, saidhead having means for discharging an atomized liquid product outwardlybeyond said discharge conduit and across said orifice, and means fordirecting a gaseous drying medium through said orifice outwardly acrossthe atomized product against the inner peripheryof the chamber in' anouter spiral down along said periphery to the lower portion of thechamber,

cross-section havingy the upper portion of its interior unobstructed, anouter intake conduit extendingy axially downwardly into said upperportion, a discharge conduit within and substantially concentric withsaid outer conduit whereby a substantially annular intake orifice isprovided between said conduits, a distributor head suplported adjacentto, but beneath, said conduits,

said hea'd having means for discharging an atomized liquid productoutwardly beyond said discharge conduit and across said orifice, meansfor rotating said head, means for directing a gaseous medium throughsaid orifice, across the atomized product andv against the innerperiphery of the chamber in an outer spiral downalong said periphery tothe lower portion of the chamber and thence spirally upwardly withinsaid outer spiral and in contact therewith to said discharge conduit,and means for assisting in moving said medium in said inner spiral tosaid discharge conduit comprising fan blades carried by saidrotatingvhead, whereby atomized particles will be dehydrated andcentrifugally thrown from the outer spiral to the wall of the chamberand from the inner to the outer spiral and thence to the wall of thechamber and gravitate to the bottom thereof.

8; In a system for dehydrating liquid products, a dehydrating chamber ofsubstantially circular cross-section having the upper portion of itsinterior unobstructed, Van outer intake conduit extending axiallydownwardly into said upper portion, a discharge conduit within andsubstantially concentric with said outer conduit whereby a'substantiallyannular intake orice is provided between said conduits, adistributor head supported adjacent to, but beneath, said conduits,saidhead having means for discharging an atomized liquid product`outwardly beyond said discharge conduit and across said orice, meansfor directing a gaseous medium through said oritice, across the atomizedproduct and against the inner periphery of the chamber in an outerspiral down along said periphery to the lower portion of the chamber andthence spirally upwardly within said outer spiral and in contacttherewith to said discharge conduit, and means for assisting in movingsaid medium in said inner spiral to said discharge conduit comprising anexhaust fan having blades extending radially in said dise chargeconduit, wherebyl atomized particles will be dehydrated andcentrifugally thrown from the outer spiral to the wall of the chamberand from the inner tothe outer spiral and thence to the wallof thechamber and gravitate to the bottom thereof.

9. In a system for dehydrating liquid prod-4 ucts, a dehydrating chamberof substantially circular cross-section having the upper portion cf itsinterior unobstructed, an outer intake conduit extending axiallydownwardly into said upper portion, a discharge conduit within ansubstantially concentric with said outer conduit whereby a substantiallyannular intake orifice is provided between said conduits, rotatablemeans comprising a combined distributor head and fan supported adjacentto, but beneath, said conduits and having nozzles for discharging anatomized liquid product outwardly beyond said discharge conduit andacross said orifice; means for directing a gaseous medium through saidorifice, across the atomized product and against the inner periphery ofthe chamber in an outer spiral down along said periphery to the lowerportion of the chamber and thence spiraliy upwardly within said outerspiral and in contact therewith to said discharge conduit, and means forassistingA in moving said medium in said inner spiral to said dischargeconduit comprising radiating arms forming part of said rotatable means,said arms supplying the liquid product to said nozzles and forming theblades of said fan, whereby atomized particles will be dehydrated andcentrifugally thrown from the outer spiral to the wall of the chamberand from the inner to the outer spiral and thence to the wall of thechamber and gravitate to the bottom thereof.

10. In a system for dehydrating liquid products, a dehydrating chamberof substantially circular cross-section having vthe upper portion of itsinterior unobstructed, an outer intake conduit and an innersubstantially concentric dis-v charge conduit both extending axiallydown` wardly intosaid upper portion and having their y inner endsoutwardly ared whereby a substantially annular intake orifice isprovided between said ends, rotatable means comprising a comi bine'ddistributor head and Afan supported adjacent to, but beneath, said endsand having nozzles arranged outwardly beyond the inner con- V duit fordischarging an atomized liquid product across said orice, means fordirecting a gaseous medium through said orifice, across the atomizedproduct and against the inner periphery of the chamber in an outerspiral down valong said periphery to the lcwer`A portion of the lchamberand thence spirally upwardly within' said outer spiral and in Vcontacttherewith to said discharge conduit, and means for assisting in movingsaid medium in said inner spiral to said discharge conduit comprisingradiating arms forming part of said rotatable means and terminating insaid nozzles for supplying the liquid product thereto and forming theblades of said fan, whereby atomized particles will be 'dehydrated andcentrifugally thrown from the outer spiral to the wall of the chamberand from the inner to the outer spiral and thence to the wall of thechamber and gravitate to therbottom thereof.

11. A method `of dehydrating a liquid product which comprisesintroducing a gaseous dryingV medium into the upper end of an internallyunobstructed chamber having a tapered lower portion, causing said mediumto flow outwardly.

from the axial zone of said chamber and to ro'- tate in a spiral currentoutwardly of said axial l' zone toward the tapered end of said chamberand within said chamber, causing said medium to return through saidlaxial zone in an inner spiral currentrotating in the same directionrasthe outer spiral current and in contact with said ,c outer spiralcurrent substantially throughout the entire length of the axis of saidinner spiral to an outlet in the upper end of said chamber and withinsaid axial' zone, augmenting the movement of said inner spiral 'currentand spraying a liquid product about the axis of. said chamber into theouter spiral current only adjacent to 'said outlet,l

whereby sprayed particles in the outer spiral cu'rrent will bedehydrated and Athrown-by centrif# ugal action against the wall of rsaidchamber for collection by gravity in the lower portion of said chamberand dried particles within said inner Y spiral will be thrown bycentrifugal action intov said outer spiral.

JOISEPH lM.

